J.T. Burton, a real estate agent with Long & Foster, was looking for a home for his growing family. The father of 6-month-old identical twin sons, Burton found what looked to be an ideal house: a four-bedroom, three-bathroom Colonial in Potomac.

In this hot market, the property should have been snapped up quickly. But there was a problem: The house had mold, and under Maryland law, the sellers were forced to disclose it. That was enough to deter potential buyers. Although the house had been under contract for $650,000, it languished on the market for nearly two months.

Unlike the other shoppers, Burton saw the problem as an opportunity to snag a good house for a discount.

Mold seems to be cropping up more often these days, and it is not only because it has been a rainy year. Experts say mold is not more prevalent these days; instead, we are more aware of it. The way new homes are built may not be helping matters. New energy-efficient homes tend to be conducive to mold growth because of their tightness, which restricts air movement.

Still, experts say that finding mold need not be panic-inducing. Understanding what it is, what causes it, how to address it and how to prevent it, they say, can help homeowners ensure that their home’s environment is healthy.

A fungus among us

Mold is not a new problem. Homeowners have been dealing with it since biblical times. Leviticus, one of the early books in the Bible, offers advice on mold.

“There’s never been a mold test that we’ve done that didn’t have any mold,” said Rob Hopkin of Poolesville-based ProTec Inspection Services. “Every house, every environment has mold spores.”

It becomes an issue when the concentration of mold spores in a home is greater than what is found outside.

Mold needs three conditions to thrive: an ideal temperature, a source of food and moisture.

“If you eliminate any one of those three, you will not have a mold problem,” Hopkin said.

If only it were that simple. The temperature in most houses is almost always ideal for mold growth. Mold feeds on dust or dirt, which is nearly impossible to eradicate from a home. That leaves moisture.

“Most people think you have to have a water intrusion or pipe burst in order to grow mold,” Barnes said. “If you have relative humidity above 60 percent and you have organic debris, which we all have, which is dust, you can grow mold.”

The Environmental Protection Agency cautions that if damp or wet building materials or furnishings are not cleaned and dried within 24 to 48 hours, the moisture can lead to mold growth. So if it takes a couple of days to notice that leaky faucet or the rainwater that seeped into the basement, mold probably exists.

“That funny smell — we usually call it a musty smell — that’s from mold spores feeding on nutrients and off-gassing,” Barnes said. “That’s the first key that the homeowner can say I’ve got something going on here.”

According to the Centers for Disease Control and Prevention, the most common indoor molds are cladosporium, penicillium, alternaria and aspergillus. Stachybotrys chartarum, often called toxic mold, is rare. This heavy, dense, black mold is most often caused by a long-term moisture problem. Foreclosed houses that have been empty for months are typically candidates for toxic mold.

“Most of the molds we see are not toxic molds,” Hopkin said. “Most of the molds we see are allergenic molds. . . . Some people are going to be sensitive to it, and others are not.”

Unfortunately, it is nearly impossible to tell what kind of mold you have by looking at it. Mold is colored by what it eats more than what it is; therefore, it is indistinguishable without testing by a professional.

Some steps to take

Mold affects people differently. For some, exposure to mold causes nothing more than itchy eyes, sneezing and coughing. For others, it can lead to asthma attacks and lung problems.

“People ask us all the time: ‘Is this a dangerous mold? Is this going to be a problem for us?’ ” Hopkin said. “The answer is: I don’t know. For some people, it likely would be. For many people, it might not.”

“Mold is a plant,” Barnes said. “If you didn’t touch it or eat it, it wouldn’t bother you. Here’s the problem: The reproductive facet of that plant shotguns spores into the air, and it’s those microbials that we breathe in that cause the problem.”

Barnes, who has given expert testimony in court cases and drives a truck with the license plate “Moldman,” said he believes many homeowners can resolve their mold issues on their own, and he does not mind helping them over the phone.

“I’m known for taking the scary out of mold,” he said.

But there are times when it is best to call in a professional because of the extent of the problem. The EPA recommends contacting a specialist if mold covers a surface greater than 10 square feet.

“The biggest thing, the absolute biggest thing in mold remediation is the evacuation of spores,” Barnes said. “Because with surface mold, you can go in, clean it up, wipe it down, put in a dehumidifier and you have done nothing to control the spores.”

He advises using a mixture of detergent and bleach to remove mold. But that is only the first step.

“If you get rid of the mold, but you do not correct the moisture problem, the mold will return,” he said.

The best way to control the presence of mold in your home is to prevent moisture from collecting. A few simple steps homeowners can take are:

●Clean gutters and extend downspouts so that they deposit water away from the home.

●Check that the grading near the foundation causes water to run away from the home and not toward it.

●Make sure the home is properly ventilated, especially the basement, with adequate air supply and return ducts.

●Run a fan to promote air circulation.

●Replace air filters regularly.

Spend a little, save a lot

The mold problem at the house in Potomac that Burton was thinking of buying was mainly a result of neglect. The then owner had moved into a retirement home and had let the maintenance of the residence lapse.

The sellers “had to disclose [the mold],” Burton said. “They basically had a blemish on the house.”

Burton bought the 1967 house for 10 percent less than the original contract and spent $6,500 to remove the mold and fix the underlying issues.

“As a result, I got a fantastic house at a fantastic price.” Burton said. “If people are more educated about [mold], then they can actually get a good deal.”

The appraisal for the home came in at $650,000, which left Burton with about $50,000 in equity the moment he closed.

“We did a full renovation of the house,” he said. “We were able to do it because we got a good price on it.”

Mold cleanup guidelines

●Fix leak or other water problems as soon as possible. Dry all items completely. Mold will begin to grow in 24 to 48 hours.

●Scrub mold off hard surfaces with detergent and water, and dry completely.

●Absorbent or porous materials, such as ceiling tiles or carpet, may have to be thrown away if they become moldy.

●Do not paint or caulk moldy surfaces.

●If you suspect that the heating, ventilation and air-conditioning (HVAC) system may be contaminated with mold, consult a professional. Do not run the HVAC system if you suspect it is contaminated.

●If you hire a professional to do the cleanup, make sure the contractor has experience with mold.

●If you see condensation or moisture collecting on windows, walls or pipes, act quickly to dry the wet surface.

●Increase ventilation or air movement by opening doors and windows when practical. Turn the heat or cooling off and just run the fan in the HVAC system.

●Cover cold surfaces, such as cold water pipes, with insulation.

●Places that are often or always damp, such as bathrooms, can be difficult to keep mold-free. Try increasing ventilation by running a fan or opening a window and cleaning frequently.

— From EPA.gov

Kathy OrtonKathy Orton is a reporter and Web editor for the Real Estate section. She covers the Washington metropolitan area housing market. Previously, she wrote for the Sports section. She came to The Washington Post in 1996 from the Los Angeles Daily News. She also worked at the Cincinnati Post. Follow